Warming Antarctic waters stunt and deform black rockcod
Feb 23rd 2026
A lab experiment at Palmer Station found that black rockcod embryos raised at 4°C hatched earlier, were smaller and showed far more developmental defects than those raised at 0°C, signaling risks for survival and the wider Southern Ocean food web.
- Researchers raised 45,000 black rockcod embryos at Palmer Station in two conditions: 0°C and 4°C, a temperature projected for the Southern Ocean in about 100 to 200 years.
- Warm-water embryos hatched faster after about 100 days versus 155 days at 0°C and were noticeably smaller at birth.
- About 60% of embryos raised at 4°C showed malformations such as spinal bends and eye and mouth defects, compared with about 20% at 0°C.
- Signs of oxygen starvation during development and physical defects are likely to reduce swimming ability and survival, increasing predation risk.
- Earlier hatching could desynchronize larvae from seasonal phytoplankton blooms, leaving hatchlings without key food sources.
- Although black rockcod are not a major commercial species, their decline could ripple across the Southern Ocean food web and reflect broader climate-driven risks to global fisheries.